In an electrical vehicle having an electrical motor used for a vehicle running, a battery to be charged is used as a driving source of the electrical motor, and the electrical motor drives the vehicle by the electrical power supplied from the battery. In this electrical vehicle, the battery is charged at a predetermining timing so that it is possible for the vehicle to be continuously run.
However, heat is generated in the battery mounted in the electrical vehicle not only in a charging, but also in a discharging where the electrical power is supplied to the electrical motor. When the temperature of the battery is excessively increased, the performance of the battery is decreased, and the life of the battery is remarkably shortened. In contrast, when the temperature of the battery is excessively decreased, the output of the battery is decreased, and a charging efficiency of the battery is also decreased. Therefore, a cooling and heating device for performing a cooling and a heating of the battery is provided in the electrical vehicle. In this electrical vehicle having the cooling and heating device of the battery, the battery is received in a receiving space, and the receiving space is controlled to be in a predetermined temperature range by the cooling and heating device.
Generally, a passenger compartment is maintained in a temperature range of 20° C.–30° C., and a suitable temperature for suitably using the battery is higher than the interior temperature of the passenger compartment. Thus, in a battery cooling system described in U.S. Pat. No. 5,937,664 (corresponding to JP-A-10-306722), air inside the passenger compartment is introduced into the receiving space of the battery, and a battery cooling is performed by using an air conditioner for performing an air conditioning operation of the passenger compartment. However, in this case, the following problem may be caused.
FIG. 16 is a time chart for explaining the problem in the battery cooling system where the battery mounted in the vehicle is cooled by introducing air inside the passenger compartment. In this battery cooling system, in a case where a blower of the vehicle air conditioner is turned ON, when a target temperature of air to be blown into the passenger compartment is lower than a predetermined temperature and when the air temperature inside the passenger compartment is higher than a predetermined temperature, it is determined that a cool-down operation (i.e., rapid cooling) is required. In this case, a compressor is operated by a maximum rotation speed (maximum compression capacity) so that cooling capacity of the passenger compartment is increased.
At this time, a cool-down request signal is output as an air-conditioning priority signal to the battery cooling system, and the battery cooling system reduces an air amount blown from a cooling fan to the battery after receiving the cool-down request signal. In contrast, when the cool-down request signal is canceled, the rotation speed of the compressor is decreased, and an air amount blown toward the battery by the cooling fan is increased. However, in this case, a heat load in the passenger compartment is increased again due to the operation of the battery cooling fan, and the air temperature inside the passenger compartment is increased again. As a result, the electrical compressor control and the temperature control inside the passenger compartment become unstable.